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    <meta charset="UTF-8">
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    <title>Document</title>
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<body>
    <script>
        var sum = 1 + 5;
        console.log(sum);
        var sum1 = '1' + 5;
        console.log(sum1);

        var str = '这是字符串';
        var str1 = '这是字符串';
        console.log(str == str1);
        console.log(str === str1);

        var arr = [1, 2, 3];
        var arr2 = [1, 2, 3];
        console.log(arr == arr2);
        console.log(arr === arr2);

        var obj = {
            name: '老王',
            age: 16
        }
        var obj1 = obj;
        console.log(obj == obj1);
        obj1.age = 18;
        console.log(obj1 === obj);

        var a;
        var b = null;
        console.log(a == b);
        console.log(a === b);
    </script>
</body>

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